1. Field of the Invention
The invention generally relates to a lens, and more particularly to a zoom lens.
2. Description of Related Art
Cameras utilize zoom lens so that a user can conveniently adjust a zoom range at different focal lengths. In addition, lenses are being developed to achieve a large field of view, and be suitable for large sensors. However, when zoom lenses are applied with large sensors, it is difficult to achieve a large zoom ratio while also achieving high image quality at each focal length. Conventional zoom lenses achieve different focal lengths, but comprise on image quality.
In addition, cameras that are used during the day and at night have been in greater demand. The lenses of the cameras must operate for both visible light and infrared light. Conventional zoom lenses have been designed for use in the visible light region, but generate chromatic aberrations near the infrared region. This causes images to not be focused when imaging at night using the infrared region.
Therefore, there is a demand for zoom lens suitable for large sensors, for example a sensor with an image circle equal or larger than 8 mm, with favourable image quality while also achieving a high zoom ratio, and operating both in the visible light region and the infrared region.